Master manufacturing method

Abstract

To manufacture an original disk formed by overlapping uneven structures having different average pitches.SOLUTION: A manufacturing method of an original disk 1 includes; a first forming step of forming a fine uneven structure 23 having a first average pitch on one side of a substrate 10; and a second forming step of forming a main recessed part 21 or a main projected part 22 having a second average pitch larger than the first average pitch on one side of the substrate 10 where the fine uneven structure 23 is formed, and forming the main recessed part 21 or the main projected part 22 while maintaining the shape of at least a part of the fine uneven structure 23 of the main recessed part 21 or the main projected part 22.SELECTED DRAWING: Figure 2A

Description

[Technical field]

[0001] The present invention relates to a method for producing a master, a master, a transferred material, and an article. [Background technology]

[0002] In recent years, as one of the microfabrication technologies, nanoimprinting technology has been developed, in which a master plate, columnar or cylindrical master plate with a fine pattern formed on its surface is pressed against a resin sheet or the like, thereby transferring the fine pattern on the master plate to a resin sheet or the like.

[0003] For example, Patent Documents 1 and 2 describe a technique for forming an etching mask on a substrate by lithography, and then etching the substrate on which the etching mask has been formed, thereby forming a concave-convex structure of a predetermined pattern on the substrate. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2016-28867 A [Patent Document 2] JP 2019-111786 A Summary of the Invention [Problem to be solved by the invention]

[0005] In various articles such as light guide plates, light diffusion plates, microlens arrays, anti-reflective (AG) films, and cell culture sheets, there are cases where excellent optical performance is required for light of different wavelengths (for example, visible light and light of a wavelength longer than visible light). In order to meet such a demand, it is conceivable to use nanoimprint technology to superimpose uneven structures having average pitches corresponding to the different wavelengths of light and transfer them to a resin sheet or the like. However, the technology described in Patent Documents 1 and 2 can only form uneven structures of a substantially fixed shape, and it is difficult to form uneven structures having different average pitches by superimposing them as described above.

[0006] The present invention has been made in consideration of the above problems, and an object of the present invention is to provide a method for producing a master in which concave-convex structures having different average pitches are formed in a superimposed manner, and a master, a transferred material, and an article. [Means for solving the problem]

[0007] A method for manufacturing a master master according to one embodiment includes a first formation step of forming a fine concave-convex structure having a first average pitch on one surface of a substrate, and a second formation step of forming main concave-convex portions or main convex portions having a second average pitch larger than the first average pitch on the surface of the substrate on which the fine concave-convex structure is formed, the main concave-convex portions being formed while maintaining the shape of at least a portion of the fine concave-convex structure in the main concave-convex portions or main convex portions.

[0008] The master master of one embodiment comprises a substrate having main concave or convex portions formed on one surface and a fine concave-convex structure formed on the main concave or convex portions, the fine concave-convex structure being formed at a first average pitch, and the main concave or convex portions being formed at a second average pitch larger than the first average pitch.

[0009] In one embodiment, the shape of the relief structure formed on one surface of the base material of the master or the inverted shape of the relief structure is transferred to the transferred product.

[0010] An article according to one embodiment comprises the transfer material described above. Effect of the Invention

[0011] According to the present invention, it is possible to provide a method for producing a master in which concave-convex structures having different average pitches are superimposed, a master, a transferred material, and an article. [Brief description of the drawings]

[0012] [Figure 1] FIG. 2 is a diagram showing a schematic external view of a master according to an embodiment of the present invention. [Figure 2A] 2 is a diagram showing an example of a concave-convex structure formed on the outer peripheral surface of the master shown in FIG. 1. [Figure 2B] 1. FIG. 4 is a diagram showing another example of the concavo-convex structure formed on the outer peripheral surface of the master shown in FIG. [Diagram 3] 2 is a diagram showing an example of the configuration of a transfer device for producing a transfer product using the master shown in FIG. 1. [Figure 4] 2 is a diagram showing an example of the configuration of an exposure device used in manufacturing the master shown in FIG. 1. [Figure 5A] 1 is a cross-sectional view (part 1) showing a method for manufacturing a master according to Comparative Example 1. FIG. [Figure 5B] 11 is a cross-sectional view (part 2) showing the method for producing a master according to Comparative Example 1. FIG. [Figure 5C] 11 is a cross-sectional view (part 3) showing the method for manufacturing a master according to Comparative Example 1. FIG. [Figure 5D] 11 is a cross-sectional view (part 4) showing the method for manufacturing a master according to Comparative Example 1. FIG. [Figure 6A] 11 is a cross-sectional view (part 1) showing a method for manufacturing a master according to Comparative Example 2. FIG. [Figure 6B] 11 is a cross-sectional view (part 2) showing the method for manufacturing a master according to Comparative Example 2. FIG. [Figure 6C] 11 is a cross-sectional view (part 3) showing the method for manufacturing a master according to Comparative Example 2. FIG. [Figure 6D] 11 is a cross-sectional view (part 4) showing the method for manufacturing a master according to Comparative Example 2. FIG. [Figure 7A]1A to 1C are cross-sectional views (part 1) illustrating an example of a method for producing a master according to an embodiment of the present invention. [Figure 7B] FIG. 2 is a cross-sectional view (part 2) showing an example of a method for producing a master according to one embodiment of the present invention. [Figure 7C] FIG. 4 is a cross-sectional view (part 3) showing an example of a method for producing a master according to one embodiment of the present invention. [Figure 7D] FIG. 4 is a cross-sectional view (part 4) showing an example of a method for producing a master according to one embodiment of the present invention. [Figure 7E] FIG. 5 is a cross-sectional view (part 5) showing an example of a method for producing a master according to one embodiment of the present invention. [Figure 7F] FIG. 6 is a cross-sectional view (part 6) showing an example of a method for producing a master according to one embodiment of the present invention. [Figure 7G] FIG. 7 is a cross-sectional view (part 7) showing an example of a method for producing a master according to one embodiment of the present invention. [Figure 7H] FIG. 8 is a cross-sectional view showing an example of a method for producing a master according to one embodiment of the present invention. [Figure 8A] 5A to 5C are cross-sectional views (part 1) illustrating another example of the method for producing a master according to one embodiment of the present invention. [Figure 8B] FIG. 4 is a cross-sectional view (part 2) showing another example of the method for producing a master according to one embodiment of the present invention. [Figure 8C] FIG. 11 is a cross-sectional view (part 3) showing another example of the method for producing a master according to one embodiment of the present invention. [Figure 9A] FIG. 2 is a SEM image of a transfer product made using the master according to Example 1. [Figure 9B] FIG. 11 is a SEM image of a transfer product made using a master according to Example 2. [Figure 10A] FIG. 13 is a SEM image of a transfer product made using a master according to Comparative Example 1. [Figure 10B] FIG. 13 is a SEM image of a transfer product made using a master according to Comparative Example 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In each drawing, the same reference numerals indicate the same or equivalent components.

[0014] FIG. 1 is a diagram showing the appearance of a master 1 according to one embodiment of the present invention.

[0015] As shown in FIG. 1, a master 1 according to this embodiment is composed of, for example, a cylindrical substrate 10 having a concave-convex structure 20 formed on an outer peripheral surface 11, which is one surface of the substrate 10.

[0016] The master 1 is a master used in, for example, a roll-to-roll imprinting technique. In the roll-to-roll imprinting technique, the outer peripheral surface 11 of the master 1 is pressed against a sheet-like substrate while rotating the master 1, thereby transferring the concave-convex structure 20 formed on the outer peripheral surface 11 of the master 1 to a sheet-like substrate or the like. According to such an imprinting technique, a transfer product to which the concave-convex structure 20 formed on the outer peripheral surface 11 of the master 1 is transferred can be efficiently manufactured.

[0017] The transferred product having the concave-convex structure 20 can be used for various purposes. For example, the transferred product having the concave-convex structure 20 can be used for products such as a light guide plate, a light diffusion plate, a microlens array, an anti-reflection film, or a cell culture sheet.

[0018] The substrate 10 is, for example, a cylindrical or columnar member. The substrate 10 may be, as shown in FIG. 1, a hollow cylindrical shape having a cavity therein. The substrate 10 may be, for example, a solid columnar shape having no cavity therein. The substrate 10 may be a flat-plate member. The substrate 10 may be, for example, made of a glass material containing SiO2 as a main component, such as fused quartz glass or synthetic quartz glass. The substrate 10 may be made of a metal, such as stainless steel. The outer peripheral surface 11 of the substrate 10 may be coated with SiO2 or the like. In the following, the substrate 10 will be described as being a cylindrical or columnar member.

[0019] It is preferable that at least the outer peripheral surface 11 of the substrate 10 is formed of a glass material mainly composed of SiO2. It is more preferable that the entire substrate 10 is formed of a glass material mainly composed of SiO2. When the main component of the substrate 10 is SiO2, the substrate 10 can be easily processed by etching using a fluorine compound. For example, the uneven structure 20 can be easily formed on the outer peripheral surface 11 of the substrate 10 by performing etching using a fluorine compound using a resist layer having a pattern corresponding to the uneven structure 20 as a mask pattern.

[0020] When the substrate 10 has a cylindrical shape, the height (axial length) of the cylindrical shape of the substrate 10 may be, for example, 100 mm or more, and the diameter (radial length perpendicular to the axial direction) of the circle on the bottom or top surface of the cylindrical shape may be 50 mm or more and 300 mm or less. When the substrate 10 has a cylindrical shape, the radial thickness of the cylinder may be 2 mm or more and 50 mm or less. However, the size of the substrate 10 is not limited to the above.

[0021] The uneven structure 20 is formed on an outer peripheral surface 11, which is one surface of the substrate 10. FIG.

[0022] As shown in FIG. 2A, the relief structure 20 includes a main recess 21 formed on the outer peripheral surface 11, which is one surface of the substrate 10, and a fine relief structure 23 formed in the main recess 21.

[0023] The main recesses 21 have a structure that slopes down from the outer circumferential surface 11 of the substrate 10 toward the inside in the radial direction of the substrate 10. The main recesses 21 have a predetermined average pitch P2 (second average pitch). The average pitch P2 of the main recesses 21 refers to the statistical average of the intervals between adjacent main recesses 21 within a predetermined range (for example, the distance between the centers of adjacent main recesses 21).

[0024] The fine concave-convex structure 23 is formed in the main recess 21. More specifically, the fine concave-convex structure 23 is formed near the bottom surface of the main recess 21. The fine concave-convex structure 23 has a predetermined average pitch P1 (first average pitch). The average pitch P1 of the fine concave-convex structure 23 refers to the statistical average of the spacing between adjacent concaves and convexities that constitute the fine concave-convex structure within a predetermined range.

[0025] As shown in FIG. 2A, a plurality of main recesses 21 each having a fine uneven structure 23 formed near the bottom surface are formed regularly or irregularly on the substrate 10.

[0026] The average pitch P1 of the fine concave-convex structure 23 is, for example, equal to or less than the wavelength of visible light. The average pitch P2 of the main recesses 21 is, for example, greater than the wavelength of visible light. Therefore, the average pitch P2 of the main recesses 21 is greater than the average pitch P1 of the fine concave-convex structure 23.

[0027] The depth H1 of the recesses constituting the fine concave-convex structure 23 ranges from about 50 nm to 300 nm, for example. The width W1 of the opening of the recesses constituting the fine concave-convex structure 23 ranges from about 50 nm to 500 nm, for example. The depth H2 of the main recess 21 ranges from about 1 μm to 20 μm, for example. The width W2 of the opening of the main recess 21 ranges from about 5 μm to 200 μm, for example. In this way, the size of the fine concave-convex structure 23 is about 1 / 10 to 1 / 4000 of the size of the main recess 21. Therefore, the concaves and convexities constituting the fine concave-convex structure 23 can be formed in units of 100 to 16 million for one main recess 21.

[0028] 2A shows an example in which the concave-convex structure 20 has a fine concave-convex structure 23 formed near the bottom surface of the main concave portion 21, but the present invention is not limited to this. As shown in Fig. 2B, the concave-convex structure 20 may have a configuration in which the fine concave-convex structure 23 is formed near the top surface of the main convex portion 22 protruding toward the radial outside of the substrate 10. In this case, the substrate 10 has a plurality of main convex portions 22, each having a fine concave-convex structure 23 formed near the top surface thereof, formed regularly or irregularly, as shown in Fig. 2B.

[0029] As described above, the master disk 1 includes a base material 10 having a main concave portion 21 or a main convex portion 22 formed on an outer peripheral surface 11 which is a single surface, and a fine uneven structure 23 formed on the main concave portion 21 or the main convex portion 22. The fine uneven structure 23 is formed with an average pitch P1 (first average pitch), and the main concave portion 21 or the main convex portion 22 is formed with an average pitch P2 (second average pitch) larger than the average pitch P1 of the fine uneven structure 23. That is, the master disk 1 has a plurality of main concave portions 21 or main convex portions 22 formed on the outer peripheral surface 11 with an average pitch P2, and each of the main concave portions 21 or main convex portions 22 is provided with the base material 10 on which the fine uneven structure 23 is formed with an average pitch P1 (P1 < P2). Therefore, the master disk 1 has uneven structures having different average pitches superimposed thereon.

[0030] In addition, in the present embodiment, as shown in FIGS. 2A and 2B, the fine uneven structure 23 is formed only on the main concave portion 21 or the main convex portion 22. That is, no fine uneven structure is formed on portions other than the main concave portion 21 or the main convex portion 22. By forming the fine uneven structure 23 only on the main concave portion 21 or the main convex portion 22 in this way, for example, a fine uneven structure such as a moth-eye structure can be formed, and a local antireflection effect can be imparted. Further, application to patterning of printing ink (Wenzel model) by utilizing the difference in wettability due to the presence or absence of the fine uneven structure is conceivable.

[0031] Next, a usage example of the master disk 1 according to the present embodiment will be described. By using the master disk 1 according to the present embodiment, a transfer product having the shape of the uneven structure 20 formed on the outer peripheral surface 11 of the master disk 1 transferred thereto can be manufactured. FIG. 3 is a diagram showing a configuration example of a transfer device 5 for manufacturing a transfer product using the master disk 1 according to the present embodiment.

[0032] As shown in FIG. 3, the transfer device 5 includes a master disk 1, a base material supply roll 51, a take-up roll 52, guide rolls 53 and 54, a nip roll 55, a peeling roll 56, an application device 57, and a light source 58. The transfer device 5 shown in FIG. 3 is a roll-to-roll type imprint device.

[0033] The substrate supply roll 51 is, for example, a roll on which a sheet-like substrate 61 is wound in a roll shape. The winding roll 52 is a roll that winds up a transfer product in which a resin layer 62 to which the uneven structure 20 of the master 1 is transferred is laminated. The guide rolls 53 and 54 are rolls that transport the sheet-like substrate 61 before and after the transfer. The nip roll 55 is a roll that presses the sheet-like substrate 61 to which the resin layer 62 is laminated against the master 1. The peeling roll 56 is a roll that peels off the sheet-like substrate 61 to which the resin layer 62 is laminated from the master 1 after the uneven structure 20 is transferred to the resin layer 62.

[0034] The coating device 57 includes a coating means such as a coater, and coats the photocurable resin composition on the sheet-like substrate 61 to form a resin layer 62. The coating device 57 may be, for example, a gravure coater, a wire bar coater, or a die coater. The light source 58 is a light source that emits light of a wavelength capable of curing the photocurable resin composition. The light source 58 may be, for example, an ultraviolet lamp.

[0035] The photocurable resin composition is a resin that is cured by irradiation with light of a specific wavelength. The photocurable resin composition may be, for example, an ultraviolet-curable resin such as an acrylic acrylate resin or an epoxy acrylate resin. The photocurable resin composition may contain, as necessary, a polymerization initiator, a filler, a functional additive, a solvent, an inorganic material, a pigment, a static inhibitor, or a sensitizing dye.

[0036] The resin layer 62 may be formed of a thermosetting resin composition. In this case, the transfer device 5 is provided with a heater instead of the light source 58. The resin layer 62 is heated by the heater to harden the resin layer 62, and the relief structure 20 can be transferred. The thermosetting resin composition may be, for example, a phenol resin, an epoxy resin, a melamine resin, or a urea resin.

[0037] In the transfer device 5 shown in FIG. 3, a sheet-like substrate 61 is continuously sent from a substrate supply roll 51 through a guide roll 53. A photocurable resin composition is applied to the sent-out sheet-like substrate 61 by an application device 57, and a resin layer 62 is laminated on the sheet-like substrate 61. The sheet-like substrate 61 on which the resin layer 62 is laminated is pressed against the master 1 by a nip roll 55. As a result, the concave-convex structure 20 formed on the outer peripheral surface 11 of the master 1 is transferred to the resin layer 62. The resin layer 62 to which the concave-convex structure 20 is transferred is cured by irradiation of light from a light source 58. As a result, an inverted structure of the concave-convex structure 20 of the master 1 is formed in the resin layer 62. The sheet-like substrate 61 to which the concave-convex structure 20 is transferred is peeled off from the master 1 by a peeling roll 56, sent to a winding roll 52 through a guide roll 54, and wound up.

[0038] According to such a transfer device 5, the concave-convex structure 20 formed on the outer peripheral surface 11 of the master 1 can be efficiently transferred to the sheet-like substrate 61. The concave-convex structure formed on the transferred product to which the concave-convex structure 20 of the master 1 has been transferred may be further transferred to produce a transferred product having the same concave-convex structure as the master 1. That is, the transferred product produced using the master 1 according to this embodiment includes a transferred product to which the shape of the concave-convex structure 20 formed on the outer peripheral surface 11, which is one surface of the substrate 10 of the master 1, has been transferred, and a transferred product to which the inverted shape of the concave-convex structure 20 has been transferred (a transferred product having the same concave-convex structure as the master 1). A transferred product having the same concave-convex structure as the master 1 can be used, for example, as a replica master.

[0039] Next, a method for manufacturing the master 1 according to this embodiment will be described.

[0040] In this embodiment, a resist layer formed on the outer peripheral surface 11 of the master 1 is exposed to light by lithography to form a latent image, and the resist layer developed after the formation of the latent image is used as an etching mask to etch the substrate 10, thereby forming a relief structure 20 on the substrate 10. Hereinafter, the configuration of the exposure device 3 for exposing the resist layer described above will be described with reference to FIG.

[0041] As shown in FIG. 4, the exposure device 3 includes a laser light source 31, a first mirror 33, a photodiode (PD) 34, a condenser lens 36, a collimator lens 38, an electro-optic deflector (EOD) 39, a second mirror 41, a beam expander (BEX) 43, and an objective lens 44.

[0042] The laser light source 31 is controlled by an exposure signal generated by a control mechanism 47. The laser light 30 emitted from the laser light source 31 is irradiated onto the substrate 10 placed on a turntable 46. The turntable 46 on which the substrate 10 is placed is rotated by a spindle motor 45 controlled by a rotation control signal synchronized with the exposure signal.

[0043] The laser light source 31 is a light source that emits laser light 30 that exposes the resist layer formed on the outer peripheral surface 11 of the substrate 10. The laser light source 31 may be, for example, a semiconductor laser light source that emits laser light with a wavelength belonging to the blue light band of 400 nm to 500 nm. The laser light 30 emitted from the laser light source 31 travels straight as a parallel beam and is reflected by a first mirror 33.

[0044] The laser light 30 reflected by the first mirror 33 is focused on an electro-optical polarizing element 39 by a focusing lens 36, and then collimated again by a collimator lens 38. The collimated laser light 30 is reflected by a second mirror 41 and guided horizontally to a beam expander 43.

[0045] The first mirror 33 is composed of a polarizing beam splitter and has a function of reflecting one polarized component and transmitting the other polarized component. The polarized component transmitted through the first mirror 33 is photoelectrically converted by a photodiode 34, and the photoelectrically converted light receiving signal is input to the laser light source 31. This allows the laser light source 31 to adjust the output of the laser light 30 based on feedback from the input light receiving signal.

[0046] The electro-optical polarizing element 39 is an element capable of controlling the irradiation position of the laser light 30 at a distance of about nanometers. The exposure device 3 is capable of finely adjusting the irradiation position of the laser light 30 irradiated onto the substrate 10 by using the electro-optical polarizing element 39.

[0047] The beam expander 43 shapes the laser light 30 guided by the second mirror 41 into a desired beam shape, and irradiates the laser light 30 via an objective lens 44 onto a resist layer formed on the outer circumferential surface 11 of the substrate 10.

[0048] The turntable 46 supports the substrate 10, and is rotated by the spindle motor 45 to rotate the substrate 10. The turntable 46 moves the irradiation position of the laser light 30 in the axial direction of the substrate 10 (i.e., the direction of the arrow R) while rotating the substrate 10, thereby enabling exposure to be performed in a spiral shape on the outer circumferential surface 11 of the substrate 10. The irradiation position of the laser light 30 may be moved by moving a laser head including the laser light source 31 along a slider.

[0049] The control mechanism 47 controls the output intensity and the irradiation position of the laser light 30 by controlling the laser light source 31. The control mechanism 47 includes a formatter 48 and a driver 49.

[0050] The driver 49 controls the emission of the laser light 30 by the laser light source 31 based on the exposure signal generated by the formatter 48. For example, the driver 49 may control the laser light source 31 so that the output intensity of the laser light 30 increases as the waveform amplitude of the exposure signal increases. The driver 49 may control the irradiation position of the laser light 30 by controlling the emission timing of the laser light 30 based on the waveform shape of the exposure signal. The larger the output intensity of the laser light 30, the larger the size and depth of the latent image formed in the resist layer can be.

[0051] The spindle motor 45 rotates the turntable 46 based on the rotation control signal. The spindle motor 45 may control the rotation so that the turntable 46 rotates once when a predetermined number of pulses are input by the rotation control signal. The rotation control signal can be generated from a reference clock signal common to the exposure signal, and thus generated so as to be synchronized with the exposure signal.

[0052] According to the exposure apparatus 3 shown in FIG. 4, it is possible to form a latent image of any pattern on the outer peripheral surface 11 of the substrate 10 with high accuracy and high reproducibility.

[0053] Next, a method for manufacturing the master 1 according to this embodiment will be described. In the method for manufacturing the master 1 according to this embodiment, the formation of an etching mask by exposing and developing an inorganic resist layer by thermal lithography and the formation of an etching mask by exposing and developing an organic resist layer by photolithography are combined to form the concavo-convex structure 20 having a shape in which the above-mentioned two concavo-convex patterns with different average pitches are superimposed on the outer peripheral surface 11 of the master 1. First, for comparison, a method for manufacturing a master in which an etching mask is formed by exposing and developing an organic resist layer by photolithography will be described with reference to Figs. 5A to 5D.

[0054] As shown in Fig. 5A, an organic resist layer 26 made of an organic material is formed on the outer peripheral surface 11, which is one surface of the substrate 10. As the organic material constituting the organic resist layer 26, for example, a novolac resist or a chemically amplified resist can be used. The organic material as described above can be formed into the organic resist layer 26 by, for example, using a spin coating method. In this embodiment, the organic resist layer 26 is a positive resist.

[0055] Next, as shown in FIG. 5B, the organic resist layer 26 formed on the outer peripheral surface 11 of the substrate 10 is irradiated with a laser beam 30, and the organic resist layer 26 is exposed by photolithography. The exposure can be performed by the exposure device 3 described with reference to FIG. 4. In photolithography, the organic resist layer 26 is altered by irradiation with the laser beam 30, and a latent image 26a is formed. The wavelength of the laser beam 30 is not particularly limited, but may be a wavelength belonging to the blue light band of 400 nm to 500 nm. By modulating the control signal of the laser beam 30, the output intensity and irradiation position of the laser beam 30 can be controlled, and the size and position of the latent image 26a formed on the organic resist layer 26 can be controlled. Therefore, the light source that emits the laser beam 30 may be, for example, a semiconductor laser light source whose output is easily adjustable.

[0056] Since the intensity of light is greater toward the center of the spot SP (irradiation range) of the irradiated laser light 30, the depth of the latent image 26a becomes deeper toward the center of the spot SP of the laser light 30 in a cross-sectional view, as shown in FIG. 5B. That is, the latent image 26a is formed in a semicircular shape. In addition, the organic resist layer 26 is exposed not only to the spot SP of the laser light 30, but also to the peripheral portion of the spot SP. Therefore, the range of the latent image 26a becomes wider than the range of the spot SP of the laser light 30.

[0057] Next, the organic resist layer 26 on which the latent image 26a is formed is developed, so that a recess 26b corresponding to the latent image 26a is formed in the organic resist layer 26 as shown in FIG. 5C. For developing the organic resist layer 26, an alkaline solution such as an aqueous solution of TMAH (TetraMethylAmmonium Hydroxide) or various organic solvents such as esters or alcohols can be used. When the organic resist layer 26 is a positive resist, the exposed portion exposed to the laser light 30 dissolves faster in a developer than the non-exposed portion not exposed to the laser light 30. Therefore, the exposed portion is removed by the development process. This forms the organic resist layer 26 from which the latent image 26a has been removed. Note that when the organic resist layer 26 is a negative resist, the exposed portion exposed to the laser light 30 dissolves faster in a developer than the non-exposed portion not exposed to the laser light 30. Therefore, the non-exposed portion is removed by the development process. This makes it possible to leave the latent image 26a.

[0058] Next, the substrate 10 is etched using the developed organic resist layer 26 as an etching mask (first etching mask). In this way, as shown in FIG. 5D, a recess 24 corresponding to the latent image 26a is formed in the substrate 10. The etching of the substrate 10 may be performed by either dry etching or wet etching. When the substrate 10 is a glass material mainly composed of SiO2 (e.g., quartz glass, etc.), the etching of the substrate 10 may be performed by dry etching using a carbon fluoride gas or wet etching using hydrofluoric acid or the like.

[0059] 5A to 5D, the method for manufacturing a master described with reference to Fig. 5A to 5D only forms recesses 24 wider than the range of the spot SP of the laser light 30 as a concave-convex structure on the substrate 10. Therefore, it is difficult to manufacture a master 1 in which concave-convex structures having different average pitches are superimposed on each other by the method for manufacturing a master described with reference to Fig. 5A to 5D.

[0060] Next, a method for producing a master, in which an etching mask is formed by exposing and developing an inorganic resist layer by thermal lithography, will be described with reference to FIGS. 6A to 6D.

[0061] As shown in FIG. 6A, an inorganic resist layer 27 made of an inorganic material is formed on the outer peripheral surface 11, which is one surface of the substrate 10. As the inorganic material constituting the inorganic resist layer 27, for example, a metal oxide containing one or more transition metals such as tungsten (W) or molybdenum (Mo) can be used. The inorganic material as described above can be formed as the inorganic resist layer 27 by using, for example, a sputtering method. In this embodiment, the inorganic resist layer 27 is a positive resist.

[0062] Next, as shown in Fig. 6B, the inorganic resist layer 27 formed on the outer peripheral surface 11 of the substrate 10 is irradiated with a laser beam 30, and the inorganic resist layer 27 is exposed by thermal lithography. The exposure can be performed by the exposure device 3 described with reference to Fig. 4. In thermal lithography, the inorganic resist layer 27 is altered by the heat of the irradiated laser beam 30, and a latent image 27a is formed. As the laser beam 30, the same laser beam 30 used in the optical lithography described with reference to Fig. 5B can be used.

[0063] Within the spot SP (irradiation range) of the irradiated laser light 30, the temperature distribution is not uniform but biased. Therefore, in the part of the spot SP of the laser light 30 where the temperature is high, the inorganic resist layer 27 is altered and a latent image 27a is formed. Furthermore, the depth of the latent image 27a becomes deeper as the temperature increases. Therefore, the range of the latent image 27a is narrower than the range of the spot SP of the laser light 30, and the depth also varies within the latent image 27a.

[0064] Next, by developing the inorganic resist layer 27 on which the latent image 27a is formed, as shown in Fig. 6C, a recess 27b corresponding to the latent image 27a is formed in the inorganic resist layer 27. For example, an alkaline solution such as a TMAH aqueous solution can be used to develop the inorganic resist layer 27.

[0065] Next, the substrate 10 is etched using the developed inorganic resist layer 27 as an etching mask. In this way, as shown in Fig. 6D, a recess 25 corresponding to the latent image 27a is formed in the substrate 10. The etching of the substrate 10 may be performed by either dry etching or wet etching.

[0066] 6A to 6D, only recesses 25 smaller than the range of the spot SP of the laser light 30 are formed as a concave-convex structure on the substrate 10. Therefore, it is difficult to manufacture a master 1 in which concave-convex structures having different average pitches are superimposed on each other using the master manufacturing method described with reference to Fig. 6A to 6D.

[0067] Next, a method for manufacturing the master 1 according to this embodiment will be described below. Hereinafter, an example will be described in which a master 1 having a concave-convex structure 20 in which a fine concave-convex structure 23 is formed in main recesses 21, as shown in FIG. 2A, is manufactured.

[0068] The manufacturing method of the master 1 according to this embodiment includes a first forming step and a second forming step. In the first forming step, a fine concave-convex structure 23 having a predetermined average pitch P1 (first average pitch) is formed on the outer peripheral surface 11, which is one surface of the substrate 10. In the second forming step, a main concave portion 21 or a main convex portion 22 having a predetermined average pitch P2 (second average pitch) larger than the average pitch P1 is formed on the outer peripheral surface 11 of the substrate 10 on which the fine concave-convex structure 23 is formed. Here, in the second forming step, the main concave portion 21 or the main convex portion 22 is formed while maintaining the shape of at least a part of the fine concave-convex structure 23 in the main concave portion 21 or the main convex portion 22. The first forming step and the second forming step will be described in more detail below.

[0069] First, the first forming step will be described with reference to Figures 7A to 7D.

[0070] As shown in Fig. 7A, an inorganic resist layer 27 is formed on the outer peripheral surface 11, which is one surface of the substrate 10. The inorganic resist layer 27 can be formed by, for example, the method described with reference to Fig. 6A.

[0071] Next, as shown in FIG. 7B, the inorganic resist layer 27 formed on the outer peripheral surface 11 of the substrate 10 is irradiated with a laser beam 30 (not shown), and the inorganic resist layer 27 is exposed by thermal lithography. The exposure can be performed by the exposure device 3 described with reference to FIG. 4. The inorganic resist layer 27 is altered by the heat of the irradiated laser beam 30, and a latent image 27a is formed. As described above, the latent image 27a formed by thermal lithography can be made smaller in size than the spot SP of the laser beam 30. The latent image 27a is formed corresponding to the fine uneven structure 23.

[0072] Next, by developing the inorganic resist layer 27 on which the latent image 27a is formed, as shown in Fig. 7C, a recess 27b corresponding to the latent image 27a is formed in the inorganic resist layer 27. The development of the inorganic resist layer 27 can be performed by, for example, the method described with reference to Fig. 6C.

[0073] Next, the substrate 10 is etched using the developed inorganic resist layer 27 as an etching mask (first etching mask). In this way, as shown in FIG. 7D, recesses 23a corresponding to the latent images 27a are formed in the substrate 10. The recesses 23a correspond to the fine uneven structure 23. The etching of the substrate 10 may be performed by either dry etching or wet etching.

[0074] Thus, the first forming step includes a first deposition step (FIG. 7A), a first exposure step (FIG. 7B), a first development step (FIG. 7C), and a first etching step (FIG. 7D).

[0075] In the first film-forming step, an inorganic resist layer 27 is formed on the outer peripheral surface 11, which is one surface of the substrate 10. In the first exposure step, the inorganic resist layer 27 is exposed by thermal lithography to form a latent image 27a corresponding to the fine relief structure 23. In the first development step, the inorganic resist layer 27 on which the latent image 27a has been formed is developed. In the first etching step, the substrate 10 is etched using the developed inorganic resist layer 27 as an etching mask (first etching mask) to form the fine relief structure 23.

[0076] The second forming step will now be described with reference to Figures 7E to 7H.

[0077] As shown in Fig. 7E, an organic resist layer 26 is formed on the outer peripheral surface 11 of the substrate 10 on which the recesses 23a (fine uneven structure 23) are formed. The organic resist layer 26 can be formed by, for example, the method described with reference to Fig. 5A.

[0078] Next, as shown in FIG. 7F, the organic resist layer 26 formed on the outer peripheral surface 11 of the substrate 10 is irradiated with a laser beam 30 (not shown), and the organic resist layer 26 is exposed by photolithography. The exposure can be performed by the exposure device 3 described with reference to FIG. 4. The organic resist layer 26 is altered by the irradiation of the laser beam 30, and a latent image 26a is formed. As described above, the latent image 26a formed by photolithography is larger in size than the spot SP of the laser beam 30. The latent image 26a is formed corresponding to the main recess 21.

[0079] Next, by developing the organic resist layer 26 on which the latent image 26a is formed, as shown in Fig. 7G, a recess 26b corresponding to the latent image 26a is formed in the organic resist layer 26. The development of the organic resist layer 26 can be performed by, for example, the method described with reference to Fig. 5C.

[0080] Next, the substrate 10 is etched using the developed organic resist layer 26 as an etching mask (second etching mask). In this way, the main recess 21 is formed in the substrate 10 as shown in FIG. 7H. In the step shown in FIG. 7H, the substrate 10 is etched so that the etching rate of the organic resist layer 26 is greater than the etching rate of the substrate 10. By adjusting the etching rates of the organic resist layer 26 and the substrate 10 in this way, the main recess 21 can be formed while maintaining the shape of at least a part of the recess 23a (fine uneven structure 23) in the main recess 21. In addition, the fine uneven structure 23 formed in a part other than the main recess 21 can be removed. As a result, at least a part of the recess 23a formed in a position corresponding to the main recess 21 is formed in the main recess 21 as the fine uneven structure 23. That is, the substrate 10 is fabricated in which the main recess 21 is formed on one surface (the outer peripheral surface 11) and the fine uneven structure 23 is formed in the main recess 21.

[0081] Thus, the second forming step includes a second deposition step (FIG. 7E), a second exposure step (FIG. 7F), a second development step (FIG. 7G), and a second etching step (FIG. 7H).

[0082] In the second film-forming step, an organic resist layer 26 is formed on the outer peripheral surface 11, which is one surface of the substrate 10 on which the recesses 23a (fine relief structure 23) are formed. In the second exposure step, the organic resist layer 26 is exposed by photolithography to form a latent image 26a corresponding to the main recesses 21. In the second development step, the organic resist layer 26 on which the latent image 26a is formed is developed. In the second etching step, the substrate 10 is etched using the developed organic resist layer 26 as an etching mask (second etching mask) to form the main recesses 21. Here, in the second etching step, the main recesses 21 are formed while maintaining the shape of at least a portion of the recesses 23a (fine relief structure 23) in the main recesses 21.

[0083] It should be noted that the latent image 26a formed by exposing and developing the organic resist layer 26 is not limited to the example shown in FIG. 7F.

[0084] 8A, the latent image 26a may be formed so as to extend from the surface of the organic resist layer 26 to the outer peripheral surface 11 of the substrate 10. In this case, the wall surface of the latent image 26a may be formed so as to be approximately perpendicular to the outer peripheral surface 11 of the substrate 10. The steps up to the formation of the organic resist layer 26 are the same as those described with reference to FIGS. 7A to 7E, and therefore will not be described.

[0085] 8A is formed, the organic resist layer 26 is developed, and then a recess 26b reaching the substrate 10 is formed in the organic resist layer 26 as shown in FIG. 8B. The wall surface of the recess 26b is approximately perpendicular to the outer peripheral surface 11 of the substrate 10.

[0086] By performing etching using the developed organic resist layer 26 as an etching mask, it is possible to manufacture a substrate 10 having a fine relief structure 23 formed in the main recesses 21, as shown in Fig. 8C. That is, it is possible to manufacture a master 1 including a substrate 10 having a main recess 21 formed on one surface (outer peripheral surface 11) and a fine relief structure 23 formed in the main recess 21. Note that, in the substrate 10 in Fig. 8C, unlike the substrate 10 shown in Fig. 7H, the wall surface of the main recess 21 is approximately perpendicular to the outer peripheral surface 11 of the substrate.

[0087] In the development of the organic resist layer 26 shown in Fig. 8B, the organic resist layer 26 is made a negative resist, so that the portions other than the latent image 26a can be removed. Then, by etching the substrate 10, etching proceeds from the portions other than the latent image 26a, so that the substrate 10 having the fine relief structure 23 formed on the main convex portion 22 as shown in Fig. 2B can be produced.

[0088] As described above, the manufacturing method of the master 1 according to this embodiment includes a first forming step and a second forming step. In the first forming step, a fine concave-convex structure 23 having an average pitch P1 (first average pitch) is formed on one surface (outer peripheral surface 11) of the substrate 10. In the second forming step, a main concave-convex portion 21 or a main convex portion 22 having an average pitch P2 (second average pitch) larger than the average pitch P1 is formed on one surface (outer peripheral surface 11) of the substrate 10 on which the fine concave-convex structure 23 is formed. In the second forming step, the main concave-convex portion 21 is formed while maintaining the shape of at least a part of the fine concave-convex structure 23 in the main concave-convex portion 21 or the main convex portion 22.

[0089] A master 1 having overlapping recessed and projected structures with different average pitches can be manufactured by forming the main recessed and projected portions 21 or the main projected portions 22 while maintaining the shape of the fine recessed and projected structure 23 in the main recessed and projected portions 21 or the main projected portions 22. Furthermore, by using such a master 1, a transfer having overlapping recessed and projected structures with different average pitches, and an article including such a transfer can be manufactured. EXAMPLES

[0090] Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples.

[0091] [Master production] Example 1 The master according to Example 1 was produced by the following process. First, a tungsten oxide film was formed to a thickness of 55 nm by sputtering on the outer peripheral surface of a cylindrical substrate (axial length 100 mm, diameter φ132, thickness 4.5 mm) made of quartz glass, to form an inorganic resist layer. Next, using the exposure device 3 shown in FIG. 4, thermal lithography was performed with a laser beam from a semiconductor laser light source with a wavelength of 405 nm, and a latent image corresponding to the fine uneven structure 23 was formed in the inorganic resist layer. The rotation speed of the substrate was 900 rpm.

[0092] Next, the exposed substrate was developed at 27°C for 900 seconds using a 2.38% by mass aqueous solution of TMAH (manufactured by Tokyo Ohka Kogyo Co., Ltd.), dissolving the inorganic resist layer in the latent image portion and forming recesses in the inorganic resist layer. Next, using the developed inorganic resist layer as an etching mask, reactive ion etching (RIE) was performed using CHF3 gas (30sccm) at a gas pressure of 0.5Pa and input power of 150W, and the substrate was etched for 30 minutes. After that, the remaining inorganic resist layer was removed.

[0093] Next, a 5 μm thick AZ4210 positive resist was formed by dip coating on the outer peripheral surface of the base from which the inorganic resist layer had been removed, forming an organic resist layer. Next, photolithography was performed using a laser beam from a semiconductor laser light source with a wavelength of 405 nm using the exposure device shown in FIG. 4, forming a latent image corresponding to the main recess 21 in the organic resist layer. The rotation speed of the base was set to 900 rpm. In this example, a semicircular latent image was formed in cross section as shown in FIG. 7F.

[0094] Next, the exposed substrate was developed at 27°C for 180 seconds using a 2.38% by mass aqueous solution of TMAH (manufactured by Tokyo Ohka Kogyo Co., Ltd.), dissolving the organic resist layer in the latent image portion and forming recesses in the organic resist layer. Next, using the developed organic resist layer as an etching mask, reactive ion etching (RIE) was performed using CHF3 gas (30sccm) at a gas pressure of 0.5Pa and input power of 150W, and the substrate was etched for 300 minutes. After that, the remaining organic resist layer was removed.

[0095] Through the above steps, a master having a concave-convex structure formed on the outer circumferential surface was manufactured.

[0096] Example 2 In this example, instead of the latent image having a semicircular cross-sectional shape as shown in Fig. 7F, a latent image reaching the outer peripheral surface of the substrate and having a wall surface approximately perpendicular to the outer peripheral surface of the substrate as shown in Fig. 8A was formed as the latent image formed in the organic resist layer. The other steps were the same as those of Example 1, and the master according to Example 2 was manufactured.

[0097] Comparative Example 1 In Comparative Example 1, a master was produced by the steps described with reference to FIGS. 5A to 5D.

[0098] Specifically, an inorganic resist layer was formed on the outer peripheral surface of the same substrate as in Example 1 by the same method as in Example 1. Next, thermal lithography was performed by the same method as in Example 1 to form a latent image in the inorganic resist layer. Next, development and etching of the inorganic resist layer were performed by the same method as in Example 1 to produce a master according to Comparative Example 1.

[0099] Comparative Example 2 In Comparative Example 2, a master was produced by the steps described with reference to FIGS. 6A to 6D.

[0100] Specifically, an organic resist layer was formed on the outer peripheral surface of the same substrate as in Example 1 by the same method as in Example 1. Next, photolithography was performed by the same method as in Example 1 to form a latent image in the organic resist layer. Next, development and etching of the organic resist layer were performed by the same method as in Example 1 to produce a master according to Comparative Example 2.

[0101] [Production of transcripts] Transfers were produced using the masters according to Examples 1 and 2 and Comparative Examples 1 and 2. Specifically, the concave-convex structure formed on the outer peripheral surface of the master was transferred to an ultraviolet curing resin using a transfer device 5 shown in FIG. 3. A polyethylene terephthalate (PET) film was used as the sheet-like substrate for the transfer. The ultraviolet curing resin was heated to 1000 mJ / cm by a metal halide lamp. 2 The resin was cured by exposure to ultraviolet light for 1 minute.

[0102] [Evaluation Results] 9A, 9B, 10A, and 10B show images of the transfers produced using Examples 1 and 2 and Comparative Examples 1 and 2 observed by a scanning electron microscope (SEM). FIG. 9A is an SEM image of the transfer produced using the master according to Example 1, taken at a magnification of 1000 times. FIG. 9B is an SEM image of the transfer produced using the master according to Example 2, taken at a magnification of 10,000 times. FIG. 10A is an SEM image of the transfer produced using the master according to Comparative Example 1, taken at a magnification of 1000 times. FIG. 10B is an SEM image of the transfer produced using the master according to Comparative Example 2, taken at a magnification of 10,000 times.

[0103] 9A and 9B, in the transfer product produced using the masters according to Examples 1 and 2, a fine relief structure with a height of several hundreds of nm was formed on each of a plurality of main convex portions with a height of several μm. For example, in the transfer product produced using the master according to Example 1, a fine relief structure with a height of about 200 nm was formed on the top of a main convex portion with a height of about 2.6 μm. Therefore, it was found that the transfer products produced using the masters according to Examples 1 and 2 had relief structures with different average pitches formed in a superimposed manner.

[0104] On the other hand, referring to Fig. 10A, in the transfer product produced using the master according to Comparative Example 1, only convex portions having a height of about 3.2 µm were formed, and no uneven structure with an average pitch different from that of the convex portions was formed. Also, referring to Fig. 10B, in the transfer product produced using the master according to Comparative Example 2, only convex portions having a height of about 200 nm were formed, and no uneven structure with an average pitch different from that of the convex portions was formed.

[0105] Although the present invention has been described based on the drawings and embodiments, it should be noted that those skilled in the art can easily make various modifications or corrections based on the present disclosure. Therefore, it should be noted that these modifications and corrections are included in the scope of the present invention. [Explanation of symbols]

[0106] 1 Master 3. Exposure equipment 5 Exposure equipment 10 Base material 11 Outer surface 20 Uneven structure 21 Main recess 22 Main convex part 23 Fine uneven structure 23a Recess 24,25 Recesses in the substrate 26 Organic resist layer 26a,27a latent image 26b Recessed portion of organic resist layer 27 Inorganic resist layer 27b Recesses in inorganic resist layer 30 Laser light 31 Laser light source 33 Mirror No. 1 34 Photodiode 36 Condenser Lens 38 Collimator Lens 39 Electro-optical polarizing element 41 2nd Mirror 43 Beam Expander 44 Objective Lens 45 Spindle motor 46 Turntable 47 Control Mechanism 48 Formatter 49 Drivers 51 Substrate supply roll 52 Winding roll 53,54 Guide roll 55 Nip Roll 56 Peeling roll 57 Coating Equipment 58 Light source 61 Sheet-shaped substrate 62 Resin layer

Claims

1. A first film formation step of forming an inorganic resist layer on one surface of a substrate; a first exposure step of exposing the inorganic resist layer by thermal lithography to form a latent image corresponding to a fine relief structure having a first average pitch on one surface of the base material; a first developing step of developing the inorganic resist layer on which the latent image is formed; a first etching step of etching the base material using the developed inorganic resist layer as a first etching mask to form the fine uneven structure; a second film formation step of forming an organic resist layer on the surface of the base material on which the fine unevenness structure is formed; a second exposure step of exposing the organic resist layer by photolithography to form a latent image corresponding to major concave or convex portions having a second average pitch larger than the first average pitch; a second development step of developing the organic resist layer on which the latent image is formed; a second etching step of etching the base material using the developed organic resist layer as a second etching mask to form the main concave portion or the main convex portion; a second etching step of etching the substrate until an etching rate of the organic resist layer is greater than an etching rate of the substrate, and the substrate is etched until the fine uneven structure other than the portions corresponding to the main concave portions or the main convex portions is removed.

2. The method for producing a master according to claim 1 , the first average pitch is less than or equal to a wavelength of visible light; The method for manufacturing a master, wherein the second average pitch is larger than a wavelength of visible light.

Images